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All About Guns What's your weapon of choice, and why? Discuss the beloved speargun here!

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Old 08-22-2017, 03:04 PM   #46
z1taz
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Re: More about the inverted polispast rollers

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Originally Posted by Behslayer View Post
Mr. Alexander, sorry for the confusion, I was referring to G-Spearguns.

I know you is Marc, and G is your best friend. I know G is together with one of my friends, Poema who really is one of the nicest people I've met. So I figure you must not be so bad either. I think some friends will be coming to visit soon.

Ofcourse I do appreciate and I am interested in the work Majd does regarding Speargun Ballistics, tuning, etc. I'm interested in all Speargun development.

Aside from all of this BS..

Question for Seal and Mr. G, Marc, any of you with experience with Rollers, Inverted, Poliplast etc.. If I was going to use one Roller Power System for a Bluewater gun with the goal being distance shooting ie killing fish at 7-8mtr+ which Power System would you suggest? And what do you think is the requirement for length of the stock of the gun?
That's the Real Question we all want to answer here.
the answer is simple 130 to 135 cms for shafts 160 to 170 cms
the guns already exist and are from Itio , are the best made i ever saw on such wood guns , the little thing are the costs that could temperate some peoples !

i myself play making some inverted carbon guns and they shot the point from shaft at 9 meters from hand on a 122 or a 130 cms tubes .
i do not release those for sell as i do not appreciate the amount of time spend on building those , and i am still awaiting to received some special shafts ordered in April that are not coming fast from Hunt !

About G spearguns , the videos with some shot on wahoos or dogtooth are in FB on his private page or in some FB groups .
Yes Poema is / or ? was w G and i am sponsoring her . Same some her videos from her killing 30/35 kgs wahoos w my own made 2 rubbers carbon guns are in my FB pages .. i ll PM you the links

rgds
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Old 08-22-2017, 03:23 PM   #47
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Re: More about the inverted polispast rollers

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Everybody (famous gun builders included) can be criticized. Maybe spearfishing gun makers take it more personally than they should because the companies are usually one-man operations and have the builders' name attached to the brand.

Does Majd have a right (or even obligation) to criticize the workmanship, design, etc. of a gun? Absolutely. I don't know if the way he did it I agree with 100% but when you sell something and put it out in the world, you need to be open to all kinds of criticism. This feedback will lead to better made guns in the future if not only from the ensuing dialogue. I know I've learned a lot about gun designs from Majd's posts. There might be other people advancing speargun design, but they have a commercial interest in keeping those advancements a secret. Majd spent a lot of time on these tests and he published the results for everyone to see, all without pay. I think that deserves applause, so maybe we can go a bit easier on him if we don't agree with the way he's criticizing certain guns / companies.

I think it's very cool that Seal builds all the parts himself rather than buying off-the-shelf parts. However, this also comes with the added risk that the parts won't work or look as good as off-the-shelf parts and may take away from the gun as a whole. In the Seal gun that was received by Majd, clearly the finish of the trigger parts could've used more work.
This is not criticizing,this is something else! Normaly people who care about free public education and charity are not so rude and tricky!He didnt even ask for eventual advise and lied to me directly! Im sure many people keep silence becouse are afraid of bad advertisement.But I cant say black to the white and I stand behind my creations.I give lifetime garantie to my triggers,the rest is known by many people.I would never use somebodyelses triggers. I would never refuse reclamation or advise.
I always accept to have witnesses in my pool tests,like this one
https://www.youtube.com/watch?v=B8ORqQWHUa0&t=10s
The guy is one of biggest local importers of spearfishing gear.I dont have business with him.He is diving in the Med only with one of my guns.He wanted to be a witness himself and I didnt bribe or violate him
I have always tried to be objective as possible!I dont oblige anybody to believe to my work.My work is much more than tieing bands and playing in the pool.In fact,i start to like pool shooting.I even start to think about mooving targets)))
Soon I will film a detailed test with the gun the whole story is about!
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Old 08-22-2017, 04:14 PM   #48
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Re: More about the inverted polispast rollers

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Im sure many people keep silence becouse are afraid of bad advertisement.

the whole story is about!
yes exactly which is obviously something i agree with you seal and something nobody could say i myself do !
in fact i hate to lick others ass holes ! ha ha !
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Old 08-22-2017, 04:15 PM   #49
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Re: More about the inverted polispast rollers

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Soon I will film a detailed test with the gun the whole story is about!
Looking forward to that test Seal! Thanks!
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Old 08-22-2017, 04:47 PM   #50
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Re: More about the inverted polispast rollers

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I think the admin/site owner has showed on many occasions he is only interested in clicks and the monetary value that comes with it. Hosting this vile crap is immoral and disgusting and one of the reasons it took me forever to sign up for this forum.

The most pathetic about that is that the forum admin is well aware of how bad it is and he has not even the sense to comment on a thing that is upsetting to so many forum members.

If it is cowardness, ignorance or just plain ol' disregard... who knows?
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Old 08-22-2017, 04:56 PM   #51
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Re: More about the inverted polispast rollers

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The most pathetic about that is that the forum admin is well aware of how bad it is and he has not even the sense to comment on a thing that is upsetting to so many forum members.

If it is cowardness, ignorance or just plain ol' disregard... who knows?
Clicks make money
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Old 08-22-2017, 05:03 PM   #52
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Re: More about the inverted polispast rollers

Wonder if the advertisers know or care about that the mass click generators are threads consisting of rasist and conspiratory bs?
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Old 08-22-2017, 05:26 PM   #53
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Re: More about the inverted polispast rollers

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Originally Posted by Behslayer View Post
The Real Question here is: How does an Inverted Poliplast Power System compare to a classic set up regarding performance. (Power, Range, Accuracy, Complexity, Field Use, Maintenance, etc) And what are the parameters ie Guns under 140cm total length, Guns over 140cm Total length.
I can talk generally but as you can see there are many small differences between various rollergun manufacturers so I will rather compare my models with classical guns.

Power: Bestiarius invert model with bottomside Archimedes pulley (sorry Seal but polispast is no allround accepted ) with setup 2 bottom pairs 18 mm and one 14 mm booster band and shaft 7.5 mm thick can be compared with classical 15-20 cm longer three band speargun. On thicker shaft like 8-9 mm I put additional bottom pair of bands.

Range: in function of power so obviously .... Here in Croatia tuna spearfishing is not allowed but in Montenegro which is also on Adriatic sea is allowed and this and last year some guys had close meetings with 50-90 kg tuna. Leaved on line with 120 rollergun with 150/8,5 shaft on 5-7 m from the tip.

Accuracy: much less recoil in combination with soft trigger and ergonomic high placed handle result in better accuracy especialy outside of pool in real spearfishing conditions when shots are taken in various body positions

Complexity: are we talking of complexity of manufacturing or using? If I do not need any extra loadding hook, no extra rope for catching I think it's not any mode complicated than classic speargun. Ok, three loadings are needed...

Field use: Answer is already given, maybe just can add that bands are on normal stretching factors 330-350%, so you don't need go to gym practice few months for loading bands on 400%

Mainterance: some sweet water from time to time, silicone spray or some grease on trigger mech, changing main transmission dyneema rope every 4-5 years , changing bands no often than on classical speargun...
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Old 08-22-2017, 05:50 PM   #54
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Re: More about the inverted polispast rollers

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Originally Posted by gspearguns View Post
Power: Bestiarius invert model with bottomside Archimedes pulley (sorry Seal but polispast is no allround accepted ) with setup 2 bottom pairs 18 mm and one 14 mm booster band and shaft 7.5 mm thick can be compared with classical 15-20 cm longer three band speargun. On thicker shaft like 8-9 mm I put additional bottom pair of bands.

Range: in function of power so obviously .... Here in Croatia tuna spearfishing is not allowed but in Montenegro which is also on Adriatic sea is allowed and this and last year some guys had close meetings with 50-90 kg tuna. Leaved on line with 120 rollergun with 150/8,5 shaft on 5-7 m from the tip.
Hi,
I saw your gun in person at Andre's shop in Bali last year and was really impressed by the workmanship! I have a question: what stretch percentage do you put on the bottom 18mm rubbers? The first pair is easy to load because of the pulley advantage, but to stretch the second pair of 18mm without the pulley is difficult unless the stretch percentage is not high. Thanks!
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Old 08-22-2017, 06:35 PM   #55
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Re: More about the inverted polispast rollers

Lagfish, are you Geoff?

Thanks for the references Marc and Nevin.

Nevin, Seal, do you or any in your area have experience with this concept? Does it work or is it just for stories?
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Old 08-22-2017, 07:12 PM   #56
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Re: More about the inverted polispast rollers

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Originally Posted by Behslayer View Post
Lagfish, are you Geoff?

Thanks for the references Marc and Nevin.

Nevin, Seal, do you or any in your area have experience with this concept? Does it work or is it just for stories?
Hey Jon, I was thinking about this concept the other day. One of the things I noticed when playing with rollers on my guns is that sometimes the line or bands pull the rollers and cause them to rotate, and sometimes the line or bands slip over the rollers, especially if any sand or debris causes a little extra friction in the bearing.

For that reason, I'm not sure how well the "gearshift roller" idea in those pictures you posted would work. While being able to play with torque certainly adds a fun new dimension, the line that is exerting force on the "gearshift roller" would probably have to have some means of ensuring contact (i.e. when a bike chain meshes with the spikes on the gears to ensure it doesn't slip). Otherwise, with the amount of forces involved, I would have to assume a fair amount of energy would be lost due to slippage.

Apologies if I'm missing something fundamental or if this is way off base, just a ramble based on guesswork.
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Old 08-22-2017, 07:47 PM   #57
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Re: More about the inverted polispast rollers

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Lagfish, are you Geoff?

Thanks for the references Marc and Nevin.

Nevin, Seal, do you or any in your area have experience with this concept? Does it work or is it just for stories?
Jon,
I am not Geoff - just a newcomer to the sport who's really interested in guns . I spent 2 months in Bali earlier this year and I've been to Andre's shop a few times.

I can offer some unsolicited advice regarding the pulley system as a mechanical engineer.
I think it offers the following advantages over the pulley block:
-You can get an extra 5cm or so of band stretch for a given size gun because you don't need pulley blocks to go between the rubber and pulley
-There is a bit less mass (15g per pulley, which is very small compared to the mass of the rubbers)
-There is a bit less water resistance from the movement of the pulleys through water
-You can specify an exact gear ratio between the shaft and rubber instead of being stuck to multiples of 2:1 with the pulley block. You could even use a conical pulley to have a variable ratio to provide more force at the start of spear travel and more speed at the end of spear travel:

The DreamAir gun uses something like this but with an air powered powerplant instead of pneumatic:

It's more compelling to use a conical pulley for a rubber powered gun because the force vs. contraction speed of a pneumatic powerplant is probably much flatter than a rubber gun (think electric vs. gasoline motor). You can approximate the functionality of the conical pulley by using a large diameter rope and a small enough channel width so the rope spools in a single layer. As the rubbers contract, it will pull more rope from the pulley which will cause its effective diameter to be smaller and gear ratio to be greater, providing more speed for the spear.

-Less moving parts

Potential downsides:
-Probably less efficient because now you have 4 ropes that are spooling over themselves rather than just the plastic pulley which creates more friction
-Maybe you can get some side forces on the spear if the rope lengths are not matched or they spool on the pulleys differently on the left and right side of the gun which can potentially make the gun less accurate
-Untested concept that needs more R&D

Last edited by lagfish; 08-22-2017 at 08:16 PM.
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Old 08-22-2017, 08:51 PM   #58
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Re: More about the inverted polispast rollers

Dang, we're always happy to have Mechanical Engineers in Speargun Performance conversations. Especially ones who know how good that little lunch place is accross the street from Dre's. I lived in Bali for 23 years.

I guess we are always looking for Force Multipliers.. Essentially we are on the quest to mimic the Cam's and increases in Retraction speeds you find in Archery.
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Old 08-23-2017, 02:07 AM   #59
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Re: More about the inverted polispast rollers

Neven:Bestiarius invert model with bottomside Archimedes pulley (sorry Seal but polispast is no allround accepted )
I hope its a joke and you mean just the word is not accepted?Its true I used for first time the word "polispast",taking it from the compound bows.Thats how we call them here.
But for spearguns " Arhimede" and "Polispast" is the same thing.
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Old 08-23-2017, 03:06 AM   #60
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Re: More about the inverted polispast rollers

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Hi,
I saw your gun in person at Andre's shop in Bali last year and was really impressed by the workmanship! I have a question: what stretch percentage do you put on the bottom 18mm rubbers? The first pair is easy to load because of the pulley advantage, but to stretch the second pair of 18mm without the pulley is difficult unless the stretch percentage is not high. Thanks!
Depends of band type. I like soft Cressi S45 for bottom bands (or Picasso). In that case streching is about 340-350% for first pair and 330-340% for second/third pair of bands. It can be increased 20% easily.

Last edited by gspearguns; 08-23-2017 at 03:15 AM.
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